Monoclonal antibodies to nerve growth factor from bovine seminal plasma

Mouse monoclonal antibodies directed against nerve growth factor (beta NGF) from bovine seminal plasma have been isolated and characterized. They are produced by hybridomas derived from Sp2/0.Ag14 myeloma cells and spleen cells from BALB/c mice immunized with beta NGF which was purified by the method of Harper et al. [J. biol. Chem. 257, 8541-8548 (1982)]. Five of these hybridomas can be grown in ascites tumor form and secrete antibodies of the IgG1 or IgG2a subclass. When used to probe the components of seminal plasma extracts or purified beta NGF as separated electrophoretically on SDS gels, the antibodies react with the beta NGF band at Mr = 15,000. The antibodies bind to native bovine beta NGF, but bind very poorly to mouse beta NGF. Antibody exclusion and additive-binding experiments indicate that these antibodies bind to the 1 antigenic domain. The cell receptor binding site is probably not close to this domain, as the antibodies fail to block the biological activity of bovine beta NGF on cultures of dissociated neurons from sensory ganglia. These monoclonal antibodies define a region in which bovine beta NGF is structurally different from the closely related molecule mouse beta NGF.